The present disclosure generally relates to image sensors, and specifically to a low-power signal chain in such sensors.
Image sensors can be applied in a variety of fields, including machine vision, robotics, guidance and navigation, automotive applications, and consumer products. In “smart” image sensors, it is often desirable to integrate on-chip circuitry to control the image sensor and to perform signal and image processing on the output image.
Active pixel sensors (APS), which have one or more active transistors within the pixel unit cell, can be made compatible with CMOS technologies. An active pixel sensor is often arranged as an array of elements referred to as a pixel array. Each column of the array can be read out at one time, driven and buffered for sensing by a signal chain including a readout circuit, an output stage, and an A-to-D converter.